This question comes up constantly in pool service — and the answer is yes, with an asterisk. Pool "Alkalinity Up" products sold by brands like Clorox Pool&Spa, HTH, BioGuard, and In The Swim are all sodium bicarbonate (NaHCO3). Baking soda — Arm & Hammer, store brand, doesn't matter — is also sodium bicarbonate. The active molecule is identical. But there are practical differences worth understanding before you start buying 50-lb bags from the grocery store.
Sodium bicarbonate is sodium bicarbonate. The formula is NaHCO3 regardless of whether the bag says "Alkalinity Up," "Sodium Bicarbonate," or "Arm & Hammer Baking Soda." It dissolves in water and reacts to buffer pH by providing bicarbonate ions (HCO3-) to the water chemistry. There is no "pool-specific" version of this molecule — that's not how chemistry works.
Pool water uses bicarbonate alkalinity as its primary buffering system. When you raise total alkalinity, you're increasing the concentration of bicarbonate ions. These ions resist pH changes by neutralizing both acid and base additions. The source of the bicarbonate ions doesn't change how they work.
The single most important factor in pool chemical purchases: price per pound of active ingredient. Once you know both products are the same chemical, the analysis is purely economic.
Pool-grade sodium bicarbonate is typically 100% NaHCO3. Food-grade baking soda (ANSI/NSF certified, as used by Arm & Hammer) is typically 99–100% NaHCO3. There is no meaningful purity difference between the two for pool water treatment purposes. Pool products are not "pharmaceutical grade" — they're commodity industrial chemicals just like food-grade baking soda.
This is where the real difference lies. Compare:
| Product | Typical Price | Size | Cost per Pound |
|---|---|---|---|
| Clorox Alkalinity Up | $20–28 | 7 lbs | $2.86–4.00/lb |
| HTH Alkalinity Up | $18–25 | 7 lbs | $2.57–3.57/lb |
| Arm & Hammer Baking Soda (retail) | $6–8 | 4 lbs | $1.50–2.00/lb |
| Bulk Sodium Bicarbonate (50 lb bag) | $25–40 | 50 lbs | $0.50–0.80/lb |
On a 20,000-gallon pool that needs 6 pounds to raise alkalinity 20 ppm, the difference between branded pool Alkalinity Up and bulk sodium bicarbonate is $12–20 per treatment. For service companies treating dozens of pools per week, this adds up significantly.
Some pool-grade sodium bicarbonate is milled to a finer particle size than standard baking soda, which can speed up dissolution slightly. In practice, both dissolve quickly when broadcast across the pool surface with the pump running. This is not a meaningful practical difference.
Pool-grade products come in containers designed for handling around pools — often with resealable caps and chemical-resistant bags. Grocery-store bags aren't as rugged. For bulk professional use, proper storage in a cool, dry location is the relevant factor regardless of source.
For professional service techs treating many pools: buy food-grade or industrial-grade sodium bicarbonate in 50-lb bags from a restaurant supply, chemical distributor, or wholesale club. The savings are substantial over a season.
For homeowners buying one bag at a time: the convenience of buying Alkalinity Up at the pool store may be worth the price premium. The math changes when you're buying one 7-lb bag four times a year.
Regardless of source, the dose is the same — approximately 1.5 lbs per 10,000 gallons per 10 ppm increase in total alkalinity. Target range is 80–120 ppm for most pools (80–100 ppm is often preferred in plaster pools to keep LSI balanced).
Use PoolLens to calculate your exact dose based on your pool's gallonage and current alkalinity reading — no math required at the equipment pad.
Warning: Never add baking soda directly into the skimmer. Concentrate of any chemical in the pump basket can damage the impeller and seal. Always broadcast into the pool water directly.
PoolLens calculates exact chemical doses for your pool's size and current readings. Sodium bicarbonate, muriatic acid, and 20 more chemicals — free, offline.
Open PoolLens Free →Yes. Both Alkalinity Up (sold by Clorox, HTH, and most pool brands) and grocery-store baking soda are sodium bicarbonate (NaHCO3). The active ingredient is chemically identical.
The standard dose is approximately 1.5 pounds of sodium bicarbonate per 10,000 gallons to raise total alkalinity by 10 ppm. Use PoolLens to calculate the exact dose for your pool's volume.
Pool-grade sodium bicarbonate is typically 100% NaHCO3. Food-grade baking soda is also very high purity (typically 99%+) and is fine for pool use. The difference in purity is negligible for pool chemistry purposes.
Yes. Arm & Hammer (and any other food-grade sodium bicarbonate) works identically to branded pool Alkalinity Up. Many service techs buy it in bulk at warehouse stores for significant cost savings.
Yes, slightly. Sodium bicarbonate raises total alkalinity and has a modest pH-raising effect. At typical pool pH (7.2–7.8), adding baking soda will raise pH a small amount — usually 0.1–0.2 pH units per significant dose.